The present invention relates to a perimeter for examining a state of a visual field of a patient's eye.
When diagnosing disease such as glaucoma, examining (measuring) the state of the visual field (perimetry) is considered to be effective. As an apparatus for examining the state of the visual field (perimeter), such an apparatus is known in which a stimulation target (optotype) for examination is projected on a dome-shaped screen or is displayed on an electronic display panel such as a liquid crystal display to be presented to the patient's eye fixing to a predetermined fixation point while varying a presentation position and a presentation brightness (luminance) of the target, and the minimum brightness at which the patient can visually recognize (perceive) the presented target, that is, the threshold value of sensitivity with respect to the presentation brightness, is examined at each examination point on a retina of the patient's eye corresponding to each presentation position by obtaining whether or not patient can recognize the presented target (see U.S. Pat. No. 6,705,726 (corresponding to JP 2003-235800A)).
However, in this kind of the perimeter, since the presentation brightness of the target is gradually lowered (made darker) from a constant reference value at each of 50 to 100 examination points, it takes a long time for examination, and hence the burden on the patient is significant. Further, if it takes long time for examination and a burden on the patient is significant, reliability of the examination result is reduced.